Pooled estimates of sustained virologic response (SVR), relapse and dropouts were calculated using the random effects model, considering the variability of shortened duration, ribavirin dose, genotype and baseline viral load. In G1-slow responders, a 72 week-extended duration increased SVR (+10.7%, 95%CI:+4.4%-+17.1%), decreased relapse (-12.3%, 95%CI:-25.4%-0%), and did not significantly increase drop-out rates (+4.5%, 95%CI:-0.6%-+9.6%). The benefit of extended duration was lower when using weight-based ribavirin regimen (+8.7%, 95%CI:+1.7%-+15.8%). In G1-rapid responders, a 24 week-shortened duration decreased SVR (-12.5%, 95%CI:-19.2%--5.8%), and increased relapse rates (+8.8%, 95%CI:+2.9%- +14.8%). Such differences were not significant in patients with baseline viral load <400,000UI/mL (-4.4%, 95%CI:-9.8%-+1%). In G2/G3-rapid responders, SVR was more common for standard 24-week duration than for shortened durations (+4.1%, 95%CI:+0.1%-+8.5), but this benefit was not significant when the ribavirin was weight-adjusted and the short duration was 16 weeks (-1.7%, 95%CI:-6.1% -+2.7%), and for G2 patients (+1.6%, 95%CI: -0.2%-+5.5%).

In Conclusion, long durations of P/R therapy improve SVR, regardless of genotype. This effect is nonetheless negligible in rapid responders with the most favourable conditions for SVR (G2, G1 with low viral load, and G3 with weight-adjusted ribavirin regimen).